What are the causes of bleeding in the brain?

Hypertension is # 1: Chronic high blood pressure, alcohol abuse, bleeding from existing vascular brain lesion, primary and metastatic cancers, cerebral vasculitis (inflammatory), coagulopathies (multiple causes), low platelet count, anticoagulants (coumadin (warfarin) etc), fibrinolysis, cocaine, amphetamines, cerebral malaria, and trauma. This list is not all inclusive, but includes many of the common causes.

High blood pressure: Most commonly high blood pressure (hypertension), which puts a toll on small brain blood vessels which can rupture and bleed, usually at older age. Other causes include brain aneurysms, vascular malformations, tumors, head injury, amyloid angiopathy, use of stimulants including street drugs, medications such as blood thinners, brain surgery, cerebral venous thrombosis etc.